Deviant Behavior
by keem
Summary: Nothing ever escapes L's watchful gaze.


**A/N:** I blame this one on ZilaAssanaDyre too, as she's the one who is responsible for my infatuation with such depravity. If anything, I should thank her, because LightxSayu is delightfully taboo and I enjoy writing it far more than I probably should. Hopefully the fact that it's mildly L-centric will give a unique perspective on the pairing. Enjoy ;)

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**Deviant Behavior**

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It is the final night of surveillance for the Yagami household, and so L is watching the monitors with an especially critical eye. He plans to go over the household particularly carefully tonight, and from multiple angles, in order to comb it for potential evidence; to watch and review it several times, committing each detail to memory, no matter how tiny or seemingly insignificant it is at the time. He spotlights his attention on Light Yagami, his prime suspect, and watches the teenager idle about the house in the hours of the evening. Admittedly, he doesn't observe Light engaging in activities any more sinister than eating potato chips before dinner (_you'll ruin your appetite_, L thinks dryly, perhaps bored but unwilling to admit so._ How unspeakably scandalous_) and his efforts so far aren't exactly entertaining or conductive to the investigation in the slightest, but L has to be diligent regardless.

_You just have to slip up_, L wills, becoming surer of Light's guilt with every passing hour, even though he still lacks tangible proof for believing so. _And when you do, I will bring you to justice._

As Light retires for bed at approximately eleven PM, L begins to have his doubts. Not regarding Light's guilt (_he's definitely guilty, I just have to find the necessary evidence to convict him in court_), but as to whether he will be able to unearth any useful information regarding the method or motive.

_He's good_, L admits grudgingly. _I'll give him that._

He radios Watari to fetch him some cake, and his brain begins to power-down for the evening. Once Light falls asleep there will considerable less reason to devote his entirety to watching, and so L becomes a little restless, a little less absorbed. He still plans to monitor the Yagami boy for any potentially incriminating or suspicious behavior, but the entire endeavor seems to have been proven fruitless. L finds himself becoming distracted with other things in a mixture of depression and disappointment. Light finally closes his eyes just as Watari arrives, the elder man pushing a trolley ahead of him as he comes.

He parks the cart next to L's desk and pulls free the cover to a platter to reveal strawberry cheesecake. Beside it is a kettle of tea and a small mountain of sugar-cubes.

"Ooh, you even remembered to swirl a little whipped cream on top," L says appreciatively, sticking his finger into the fluffy white topping and licking it off of his fingers. Watari gives him a grandfatherly smile and makes his leave of L's workplace, shutting the door quietly behind him as he goes.

The unkempt detective begins making the necessary preparations regarding the tea (seven sugars, because he's rather fond of odd numbers), and then senses a flicker of movement in his peripheral. _I'll have to review that later_, he thinks, as there's a creak over the airwaves and Sayu's whisper penetrates the otherwise black silence of Light's room, amplified over L's speakers.

"Light, are you awake?"

Light clears his throat. "Yes."

L sets his tea down. _Curious_, he thinks, as his thumb is inserted between his teeth out of habit. _Very curious_.

The youngest member of the Yagami household goes tiptoeing across the floor of Light's bedroom, closing in the gap between them. L leans forward into his chair a little, taking in the scene more fully. Light shifts as far against the wall as he can on his bed as Sayu draws nearer, apparently in order to make more room. L watches in surprise as Sayu slides into bed next to her brother.

_Maybe she has nightmares_? L's mind offers helpfully, before he quickly dismisses the notion as they rummage beneath the covers_. Or maybe_—

His suspicions are confirmed when Light suddenly takes Sayu by the shoulders and steers her against his chest, pressing his lips over her own. L is glad that he put his tea down; if not, he might have dropped his cup in surprise. _Really, Light_? He thinks, with a kind of morbid fascination. _This doesn't seem like your style at all. I don't like it._

Still, if it is an clever ruse in order to steer L's suspicions away from him—an attempt to deter him from comparing profiles (Light Yagami vs. Kira, a introspective, analytical inquiry of 'what-would-Light-do', and 'what-would-Kira-NOT-do'), it isn't working in the slightest, even if it has left the detective somewhat taken aback by the display. Something of this caliber can't be an act—it's too elaborate of a hoax, and too well-rehearsed, like clockwork (_they've done this before_, L thinks, feeling vaguely uneasy. _This is a reoccurring theme_)—to be apart of a cunning plan. This—this is genuine, and L is frankly aghast by the development.

It takes a moment to compose himself. _Well, _he reasons,_ I can use this to my advantage. At the very least, I can bring him in on charges of statutory rape when the time comes_. On the screen before him, Sayu writhes beneath Light's administrations, and her quiet moans are vague and eerie over the airways.

_And I could get pinned for child pornography someday_, L thinks grimly, and makes a mental note to destroy the evidence here when he's done thoroughly reviewing it.

There is a certain finesse to Light's perversion. The way he manipulates Sayu between the sheets, the way his body contorts and moves in an almost aerobatic display. _It's too theatrical_, L realizes, _too perfectly poised_. Everything Light does is overdone: too good, too pretty, too perfect. Sex wasn't supposed to be this way. It wasn't supposed to be a tasteful portrait of desire: it was supposed to be a carnal act of passion. _This may not be an attempt on Light's behalf to simply throw my logic off, _L thinks, twirling his fork in his hand (funny, he seems to have lost his appetite for once), _but it's still ridiculous_. _Is everything you do so precise, so meticulously executed?_

"L-Light..!" Sayu cries, and arches her back. At least _she's_ real, a creature who is flawed and selfish and wanton. Meanwhile Light is an actor with memorized lines and practiced movements, mannerisms honed to perfection. _You wear a façade in everything you do, and you can change it at will, _L thinks, disgusted and perhaps a little bit impressed despite his reservations. _Here, you are embodiment of temptation: taboo and forbidden, but ultimately unable to be resisted. _

Light finishes up some moments later with just the appropriate amount of noise (a little half-gasp and sigh). His body is covered in an acceptable amount of sweat, enough to give him a pretty sheen in the moonlight but not enough to create an aversion. He eases away from Sayu and lays on his back beside her, sliding an arm around her shoulders as he does so. They linger for a bit—she clings to him fiercely in the aftermath, as he idly strokes her hair—and then she pulls on her night-clothes and slips discreetly out of his room and into the hall.

The unruly-haired detective stares at the screen long after Light falls asleep in the wake of their copulation, slightly dazed with faint disbelief over what has just transpired. Then he shakes his head and reaches for his forgotten cup. As his fingers brush the tip of the delicate china, he realizes that his tea has gone cold.

--

"And so, after extensively reviewing the video-footage regarding the surveillance of the Yagami household, I have ultimately revealed…" L pauses, and there is a tense moment in which every other occupant of the room hangs desperately onto his every word.

_An insidious, incestual affair between Light and Sayu Yagami,_ he almost says, but then decides against it at the last second. "...Absolutely nothing. The wire-taps and bugs will be removed." Chief Yagami collapses back into the chair beside the detective as the other Task Members breathe audible sighs of relief.

L chews on the edge of his fingernail. He will save the blackmail for later.


End file.
